Drive hub structure for washing machine agitator



Dec. 22, 1970 w. A. WASEMANN 3,548,617

DRIVE HUB STRUCTURE FOR WASHING MACHINE AGITATOR Filed May 5, 1968 FIG.|

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INVENTOR W||||om A.Wosem0nn FIG.2

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United States Patent O 3,548,617 DRIVE HUB STRUCTURE FOR WASHING MACHINE AGITATOR William A. Wasemann, Mansfield, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 3, 1968, Ser. No. 726,472 Int. Cl. D061: 17/08 US. Cl. 68-133 2 Claims ABSTRACT OF THE DISCLOSURE Motion transfer structure for coupling the output shaft of an upright type clothes washing machine to the agitator structure used therewith. This structure is designed to transmit rotational movement from the output shaft to the agitator without producing radial forces which tend to produce cold-flow of certain materials utilized in the fabrication of agitator structures, for example, polypropylene, the effect of the cold-flow being such as to change the operating position of the agitator thereby effecting proper operation thereof.

BACKGROUND OF THE INVENTION This invention relates, in general, to centerpost agitator type washing machines and, more particularly, to structure for transmitting motion from the output shaft to the agitator.

In the construction of a centerpost agitator washing machine, it is necessary, in some manner, to transfer the oscillating driving torque from the agitator drive shaft to the agitator. This must be accomplished in such a manner that there is no lost motion and such that the agitator can be readily disassembled by the user for cleaning purposes, the former, in prior art constructions, not being compatible with the latter.

In the past, agitators have almost entirely been made of materials such as phenolic or aluminum, which materials are relatively rigid and dimensionally stable. The motion transfer structure most commonly used in conjunction with the foregoing materials consists of a hub member (usually hexagonal in horizontal cross-section) having tapered circumferential surfaces. The neck of the agitator would have a matching shape. While the foregoing hub is satisfactory for use with such materials, it is not compatible with certain materials which are more desirable in fabrication of an agitator. An example of such a material is polypropylene.

It is well known that polypropylene is tough and resilient but it is not dimensionally stable under continued condition of stress, the effect of this instability being that of exhibiting cold-flow properties. The use of such a material with a hub structure as described above, where radial forces are transmitted to the neck of the agitator, due to the wedging effect of the taper, results in the stretching or expanding of the neck, thereby allowing the agitator to seek a new, lower and incorrect operating position.

One solution to the aforementioned problem is to provide a hub member having radially extending lugs or teeth, the outer surfaces of which are straight in lieu of being tapered. The agitator neck is provided with mating lugs or teeth internally thereof and the hub member is provided with a ledge adjacent the lower end of its teeth on which the teeth of the agitator can bottom. The problem with this solution is that, to avoid lost motion between the hub and the agitator, the teeth on the hub member and the teeth on the agitator neck would have to be held to such extremely close dimensional tolerances that manufacture of the parts would be economically prohibitive. Even if maintaining such tolerances would be economically feasible, the very slightest post-molding shrinkage of the polypropylene agitator would result in a fit so tight that it would be extremely difficult, if not impossible, for the user to remove the agitator.

A modification of the radially extending non-tapered teeth to a construction having slightly tapered teeth, substantially less than the hexagonal configuration described earlier, and further having the surfaces between adjacent teeth being slightly divergent at one end and slightly convergent at the opposite end, yielded unsatisfactory results.

The problem outlined above can be avoided altogether by providing the agitator neck with a metal insert, however, the added cost of the additional part is not desirable.

Accordingly, the general object of this invention is to provide a new and improved agitator type washing machine.

It is a more particular object of this invention to provide, in an agitator type washing machine, means for transmitting oscillatory motion from the agitator output shaft to the agitator structure without transmitting radial forces to the agitator.

SUMMARY OF THE INVENTION Briefly the above-cited objects are accomplished by providing a hub member adapted to be rigidly secured to the agitator output shaft, the hub member comprising a generally cylindrical body portion having keystone-shaped protuberances formed integrally with the circumference thereof. Adjacent protuberances delineate substantially V-shaped grooves therebetween for receiving substantially V-shaped lug elements molded integrally with the neck of a polypropylene agitator. The grooves are oriented in substantially a vertical plane and are tapered in the direction from the bottom to top thereof.

Further objects and advantages of the present invention will become apparent when considered in view of the following detailed description and drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a washing machine apparatus incorporating the invention;

FIG. 2 is a perspective view of a hub member incorporated in the invention;

FIG. 3 is a fragmentary sectional View, in perspective, of the neck portion of an agitator structure forming a part of the invention; and

FIG. 4 is an enlarged fragmentary sectional view of an agitator neck installed on the hub shown in FIG. 2 which in turn, is installed on an agitator output shaft of the machine shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, especially FIG. 1, reference character 10 designates generally an agitator washing machine. The machine 10 comprises an outer tub 11 rigidly secured to a gear housing 12 through suitable bolts 13 and 14. Together, the outer tub 11 and the gear housing 12 form a stationary structure. A pulley 16, driven by an external motor, not shown, is attached to a driving shaft 17 supported by a bearing structure 18 which extends into the lower end of a gear frame 19. Within the gear frame 19 is a gear train (not shown), the input to which is provided by the shaft 17. The general arrangement of the gear train and frame is of well known construction in the art, with the output therefrom being provided by output shaft structure 21 which drives an agitator structure 22 in an oscillating fashion, during the wash and rinse portions of the washing machine cycle. The output shaft 21 is supported by a bearing structure 23 and extends upwardly and is disposed in the center of the tub 11.

The output shaft structure 21 is of the coaxial type comprising an inner solid shaft 24 and an outer tubular shaft 26. Attached to the outer shaft 26 is a basket hub member 27 which hub member is adapted to support an inner basket 28 which is attached thereto by a plurality of bolts 29.

Attached to the inner shaft 24, by means of hub connector 31 and a hub member 32 (see FIGS. 2 and 4) is the agitator structure 22 which is made from a suitable thermoplastic material, for example, polypropylene. The hub member 32, as best illustrated in FIGS. 2 and 4 comprises a generally cylindrical body portion 33 having a central bore 34 therethrough for receiving the free end of the agitator output shaft 24, as shown in FIG. 4. The hub member further comprises a plurality of keystoneshaped protuberances 30 on the circumference of the cylindrical body portion. The protuberances are oriented such that adjacent surfaces 36 and 37 tend to diverge at the top of the hub member and tend to converge at the bottom thereof, thereby forming substantially V-shaped grooves 35. As shown in FIG. 4, surfaces 38 of the protuberances are parallel to the surface of the cylindrical body portion 33. This configuration prevents radial forces from being transmitted to the agitator structure 22 from the forces created by a hub attachment bolt 39 which is threaded substantially its entire length so that it can be screwed into the end of the shaft 24 and also into the hub connector 31. A nut and washer arrangement, indicated at 41 serves to retain the hub member 32 to the shaft 24.

The agitator structure 22 as shown in FIG. 3, comprises a neck portion 42 having molded internally thereof a plurality of V-shaped lugs or teeth 43 which are received in the V-shaped grooves 35 when the agitator 22 structure is installed on the hub member 32. As shown in FIG. 4, the grooves 35 and the lugs 43 are so dimensioned as to provide a clearance as indicated at 44, between the top of the hub member 32 and the underside of the top of the neck portion 42. Such a clearance insures a secure seating of the agitator structure 22 on the hub member 32. It will be appreciated that the hub member 32 together with the lugs 43 form means for transferring motion from the shaft 24 to the agitator structure 22.

It will now be apparent that there has been provided motion transfer means for use with a material, exhibiting cold-flow characteristics, which means does not transmit radial forces to the agitator neck and which means need not be held to such close tolerances that production thereof would be rendered economically impractical.

Since numerous changes may be made in the abovedescribed apparatus and different embodiments of the invention may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

-I claim:

1. A drive hub structure for a washing machine agitator, said hub having a generally cylindrical body portion and means on the circumference of said body portion for drivingly coupling said body portion of said agitator, said coupling means comprising:

a plurality of keystone-shaped protuberances delineating a plurality of vertically disposed grooves having opposing side surfaces which taper inwardly from top to bottom; and wherein:

said side surfaces define parallel lines when viewed in a cross-section at a right angle to the axis of said cylindrical body portion,

said parallel lines further being parallel to a radial line from the center of said hub to the respective midpoints of said grooves.

2. In combination:

a driving hub member;

a driven agitator member;

means for coupling said hub to said agitator for transmitting the oscillating motion of the former to the latter, wherein said coupling means comprises:

a plurality of V-shaped lugs having opposing tapering surfaces carried by one of said member; said opposing surfaces defining parallel lines when viewed in a cross section taken at a right angle to the axis of said members with said parallel lines further being parallel to radial lines connecting the center of said member to the respective midpoints of said lugs;

substantially V-shaped grooves having opposed tapering surfaces complementary to said opposed surfaces of said lugs carried by the other of said members;

whereby said lugs are received in said grooves for driving enagement such that no radial forces are transmitted to said agitator member.

References Cited UNITED STATES PATENTS 1,861,640 6/1932 McCabe 68133 WILLIAM I. PRICE, Primary Examiner 

